Teemo's Mushrooms HUD timer doesn't decrease at all (5 minutes all the time)

As title says,Teemo's mushrooms remain at 5 minutes in HUD select,but they keep disappearing after 5 minutes. While not harmful gameplay-wise,it bugged me out the first 10 minutes of my last Teemo game.

Edit:The timer doesn't show up in the replay,but you can still see that ALL the mushrooms have the same lenght of the timer bar http://imgur.com/cVQL9Nl